The persistence of gonorrhea, one of the most prevalent bacterial diseases reported in humans, as a major health problem has resulted in the development of numerous methods for detection of Neisseria gonorrhoeae.
Currently accepted procedures for the determination of gonococcal infection rely primarily upon culture techniques. Typical culture techniques include procedures described in Criteria And Techniques For The Diagnosis Of Gonorrhea, published by the Center for Disease Control, Atlanta, Ga. In such culture procedures, a specimen, i.e., a urethral or cervical sample, is placed on an acceptable culture medium, i.e., Thayer-Martin medium. The cultures are incubated at 37.degree. C. in a 5% carbon dioxide atmosphere for 24 to 48 hours. The culture plates are thereafter inspected for the appearance of Neisseria gonorrhoeae colonies. Suspect colonies are gram-stained and tested for oxidase activity. Generally, presumptive diagnosis of gonococcal infection in males is determined by obtaining urethral cultures which exhibit oxidase-positive colonies of gram-negative "coffee-bean" shaped diplococci when cultured on Thayer-Martin medium. In females, gonococcal infection may be diagnosed by examining cervical cultures on Thayer-Martin medium wherein oxidase-positive colonies of gram-negative diplococci appear. Organisms from presumptively identified colonies of Neisseria gonorrhoeae are frequently confirmed by sugar fermentation, fluorescent antibody staining or coagglutination. However such culture procedures are laborious, time-consuming and are generally limited to the detection of "living cells". When culture methods are utilized, a specimen may be taken at one location and shipped to a laboratory, usually at another location, where the organisms are cultured and identified. Thus, these culture procedures may require several days before results are obtained. Furthermore, results obtained from culture procedures may be erroneous, if, rather exacting conditions for preservation, shipment, and culturing of the bacteria are not followed.
In addition to culture procedures, various radiolabeled and enzymatic immunoassay procedures for the detection of Neisseria gonorrhoeae have been described. However, such procedures, such as disclosed in U.S. Pat. Nos. 4,066,744; 3,974,269; and 3,951,748 involve radio or enzymatic immunoassays wherein antibodies to Neisseria gonorrhoeae in blood serum samples are detected as a means of diagnosing gonorrhea. The results obtained from such immunoassays may be inconclusive because such procedures generally lack requisite specificity and sensitivity. False-positive or false-negative results may be obtained when antibodies to Neisseria gonorrhoeae rather than antigens are detected because antibodies are produced only in response to an infectious agent, i.e., an antigen, in the body and antibodies often remain long after the disease has been cured. Therefore, in order to accurately diagnose the presence of infection, it is preferred to assay for antigens rather than antibodies. U.S. patent application Ser. No. 905,575 describes a reverse passive hemagglutination assay for Neisseria gonorrhoeae antigens. However, this reverse passive hemagglutination assay procedure cannot be employed to directly assay clinical specimens. In accordance with the disclosed reverse passive hemagglutination assay procedure, the clinical sample must initially be cultured, and the culture is then itself assayed. In addition, since the method disclosed requires that a sample be cultured, the method possesses some of the disadvantages inherently associated with culture techniques.
Therefore, it is an object of the present invention to provide a solid phase immunoassay procedure for the detection of Neisseria gonorrhoeae antigens having the accuracy of the culture techniques but eliminating the disadvantages associated with the known immunoassay and culture procedures.